.\" $OpenBSD: route.8,v 1.39 2004/07/15 23:40:39 jmc Exp $ .\" $NetBSD: route.8,v 1.6 1995/03/18 15:00:13 cgd Exp $ .\" .\" Copyright (c) 1983, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)route.8 8.3 (Berkeley) 3/19/94 .\" .Dd March 19, 1994 .Dt ROUTE 8 .Os .Sh NAME .Nm route .Nd manually manipulate the routing tables .Sh SYNOPSIS .Nm route .Op Fl dnqSv .Ar command .Oo .Op Ar modifiers .Ar args .Oc .Sh DESCRIPTION .Nm is a utility used to manually manipulate the network routing tables. It normally is not needed, as a system routing table management daemon, such as .Xr routed 8 , should tend to this task. .Pp The .Nm utility supports a limited number of general options, but a rich command language enables the user to specify any arbitrary request that could be delivered via the programmatic interface discussed in .Xr route 4 . .Bl -tag -width Ds .It Fl d Run in debug-only mode, i.e., don't actually modify the routing table. .It Fl n Bypass attempts to print host and network names symbolically when reporting actions. (The process of translating between symbolic names and numerical equivalents can be quite time consuming, and may require correct operation of the network; thus it may be expedient to forgo this, especially when attempting to repair networking operations.) .It Fl q Suppress all output. .It Fl S Make the .Cm show command display the source selector part of the routes. .It Fl v (verbose) Print additional details. .El .Pp The .Nm utility provides several commands: .Pp .Bl -tag -width Fl -compact .It Cm add Add a route. .It Cm flush Remove all routes. .It Cm delete Delete a specific route. .It Cm change Change aspects of a route (such as its gateway). .It Cm get Lookup and display the route for a destination. .It Cm show Print out the route table similar to "netstat -r" (see .Xr netstat 1 ) . .It Cm monitor Continuously report any changes to the routing information base, routing lookup misses, or suspected network partitionings. .El .Pp The .Cm monitor command has the syntax .Bd -filled -offset indent .Nm route Op Fl n .Cm monitor .Ed .Pp The .Cm flush command has the syntax .Bd -filled -offset indent .Nm route Op Fl n .Cm flush .Op Ar family .Ed .Pp If the .Cm flush command is specified, .Nm will .Dq flush the routing tables of all gateway entries. When the address family is specified by any of the .Fl ipx , .Fl link , .Fl x25 , .Fl inet , or .Fl inet6 modifiers, only routes having destinations with addresses in the delineated family will be deleted. .Pp The other commands have the following syntax: .Bd -filled -offset indent .Nm route Op Fl n .Ar command .Op Fl net No \&| Fl host .Ar destination gateway .Ed .Pp where .Ar destination is the destination host or network and .Ar gateway is the next-hop intermediary via which packets should be routed. Routes to a particular host may be distinguished from those to a network by interpreting the Internet address specified as the .Ar destination argument. The optional modifiers .Fl net and .Fl host cause the destination to be interpreted as a network or a host, respectively. Otherwise, type is chosen based on the following rules: .Pp The route is assumed to be to a network if any of the following apply to .Ar destination : .Bl -bullet -compact .It it is the word "default", equivalent to 0/0 .It it is an IPv4 address with less than 3 dots .It it is an IPv4 address with a .Dq /XX suffix (where XX is the number of bits in the network portion of the address and is less than 32) .It it is the symbolic name of a network. .El .Pp If .Ar destination is a valid IP address or host name it is presumed to be a route to a host. .Pp If none of the above apply, .Nm prints an error message and exits. .Pp For example, .Li 192.168.1.1 is interpreted as .Fl host Li 192.168.1.1 and .Li 192.168.1 is interpreted as .Fl net Li 192.168.1 . Note, however, that .Li 192.168.2.0 will be interpreted as .Fl host Li 192.168.2.0 since it is a complete IP address with 3 dots. In this case the number of bits in the network portion of the address must be explicitly listed, for example .Li 192.168.2.0/24 , .Li 192.168.2/24 or alternately .Li 192.168.2 . .Pp If the destination is directly reachable via an interface requiring no intermediary system to act as a gateway, the .Fl interface modifier should be specified; the gateway given is the address of this host on the common network, indicating the interface to be used for transmission. .Pp The optional modifier .Fl link specifies that all subsequent addresses are specified as link-level addresses, and the names must be numeric specifications rather than symbolic names. .Pp The optional .Fl netmask qualifier is intended to manually add subnet routes with netmasks different from that of the implied network interface (as would otherwise be communicated using the OSPF or ISIS routing protocols). One specifies an additional ensuing address parameter (to be interpreted as a network mask). The implicit network mask generated in the .Dv AF_INET case can be overridden by making sure this option follows the .Ar destination parameter. .Fl prefixlen is also available for a similar purpose, for IPv6/v4. .Pp The .Fl mpath modifier needs to be specified with the .Cm add command to be able to enter multiple gateways for the same destination address (multipath). .Pp Routes have associated flags which influence operation of the protocols when sending to destinations matched by the routes. These flags may be set (or sometimes cleared) by indicating the following corresponding modifiers: .Bd -literal -cloning RTF_CLONING - generates a new route on use -xresolve RTF_XRESOLVE - emit mesg on use (for external lookup) -iface ~RTF_GATEWAY - destination is directly reachable -static RTF_STATIC - manually added route -nostatic ~RTF_STATIC - pretend route added by kernel or daemon -reject RTF_REJECT - emit an ICMP unreachable when matched -blackhole RTF_BLACKHOLE - silently discard pkts (during updates) -proto1 RTF_PROTO1 - set protocol specific routing flag #1 -proto2 RTF_PROTO2 - set protocol specific routing flag #2 -llinfo RTF_LLINFO - validly translates proto addr to link addr .Ed .Pp The optional modifiers .Fl rtt , .Fl rttvar , .Fl sendpipe , .Fl recvpipe , .Fl mtu , .Fl hopcount , .Fl expire , and .Fl ssthresh provide initial values to quantities maintained in the routing entry by transport level protocols, such as TCP or TP4. These may be individually locked by preceding each such modifier to be locked by the .Fl lock meta-modifier, or one can specify that all ensuing metrics may be locked by the .Fl lockrest meta-modifier. .Pp The .Fl src and .Fl srcmask modifiers can be used to specify the source selector of the route, which will match the source IP address of outgoing packets. .Fl src and .Fl srcmask work in a similar way to .Fl dst and .Fl netmask . For example: .Bd -literal -offset indent # route add -src 180.83.46.98 180.83.46.97 # route add -src 192.168.10/24 -dst 10.5.1/24 180.83.46.97 .Ed .Pp In a .Cm change or .Cm add command where the destination and gateway are not sufficient to specify the route, the .Fl ifp or .Fl ifa modifiers may be used to determine the interface or interface address. .Pp All symbolic names specified for a .Ar destination or .Ar gateway are looked up first as a network name using .Xr getnetbyname 3 . If this lookup fails, .Xr gethostbyname 3 is then used to interpret the name as a valid host name. .Pp .Nm uses a routing socket and the new message types .Dv RTM_ADD , .Dv RTM_DELETE , .Dv RTM_GET , and .Dv RTM_CHANGE . As such, only the superuser may modify the routing tables. .Sh FILES .Bl -tag -width "/etc/mygate" -compact .It Pa /etc/mygate Default gateway address. .El .Sh DIAGNOSTICS .Bl -diag .It "%s: gateway %s flags %x" The specified route is being added to or deleted from the tables. The values printed are from the routing table entry supplied in the .Xr ioctl 2 call. If the gateway address used was not the primary address of the gateway (the first one returned by .Xr gethostbyname 3 ) , the gateway address is printed numerically as well as symbolically. .It "%s %s done" When the .Cm flush command is specified, each routing table entry deleted is indicated with a message of this form. .It "Network is unreachable" An attempt to add a route failed because the gateway listed was not on a directly connected network. The next-hop gateway must be given. .It "not in table" A .Cm delete operation was attempted for an entry which wasn't present in the tables. .It "routing table overflow" An .Cm add operation was attempted, but the system was low on resources and was unable to allocate memory to create the new entry. .El .Sh SEE ALSO .Xr netintro 4 , .Xr route 4 , .Xr mygate 5 , .Xr routed 8 .Sh HISTORY The .Nm command appeared in .Bx 4.2 . IPv6 support was added by WIDE/KAME project. .Sh BUGS The first paragraph may have slightly exaggerated .Xr routed Ns 's abilities. .Pp Some uses of the .Fl ifa or .Fl ifp modifiers with the .Cm add command will incorrectly fail with a .Dq Network is unreachable message if there is no default route. See case .Dv RTM_ADD in .Fn route_output from .Pa sys/net/rtsock.c for details.